Abstract: An apparatus and method for inter-channel data exchange in multi-channel data acquisition systems is disclosed. A multi-channel data acquisition system may include a data exchange layer coupling two or more channels of the data acquisition system. Data may be transmitted via the data exchange layer between the channels, enabling data from one channel to be processed and output by another channel. The data exchange layer may include a serial exchange layer or a parallel exchange layer.

Abstract: An apparatus and method for inter-channel data exchange in multi-channel data acquisition systems is disclosed. A multi-channel data acquisition system may include a data exchange layer coupling two or more channels of the data acquisition system. Data may be transmitted via the data exchange layer between the channels, enabling data from one channel to be processed and output by another channel. The data exchange layer may include serial or parallel communication means.

Abstract: Methods and apparatus for reducing the thermal noise integrated on a storage element are disclosed. One embodiment of the invention is directed to a sampling circuit comprising a sampling capacitor to store a charge, the sampling capacitor being exposed to an ambient temperature. The sampling circuit further comprises circuitry to sample the charge onto the capacitor, wherein thermal noise is also sampled onto the capacitor, and wherein the circuitry is constructed such that the power of the thermal noise sampled onto the capacitor is less than the product of the ambient temperature and Boltzmann's constant divided by a capacitance of the sampling capacitor. Another embodiment of the invention is directed to a method of controlling thermal noise sampled onto a capacitor. The method comprises an act of independently controlling the spectral density of the thermal noise and/or the bandwidth of the thermal noise.

Abstract: One embodiment of the invention is directed to a method, comprising acts of generating a plurality of delay signals, and processing at least first and second delay signals of the plurality of delay signals to generate a first timing signal. Another embodiment of the invention is directed to a timing signal generator to generate a plurality of timing signals. The circuit comprises a delay signal generator to generate a plurality of delay signals, and a clock synthesizer to generate the timing signals based on selected ones of the delay signals.

Abstract: One embodiment of the invention is directed to a method comprising an act of performing digital correction of an offset in a system comprising an analog-to-digital converter (ADC) having a usable input range that is greater than a nominal input range, wherein the offset exists at an input of the ADC. Another embodiment of the invention is directed to a system comprising an ADC having a usable input range that is greater than a nominal input range, wherein an offset exists at an input of the ADC and the offset is corrected using digital correction.

Abstract: Methods and apparatus for reducing the thermal noise integrated on a storage element are disclosed. One embodiment of the invention is directed to a sampling circuit comprising a sampling capacitor to store a charge, the sampling capacitor being exposed to an ambient temperature. The sampling circuit further comprises circuitry to sample the charge onto the capacitor, wherein thermal noise is also sampled onto the capacitor, and wherein the circuitry is constructed such that the power of the thermal noise sampled onto the capacitor is less than the product of the ambient temperature and Boltzmann's constant divided by a capacitance of the sampling capacitor. Another embodiment of the invention is directed to a method of controlling thermal noise sampled onto a capacitor. The method comprises an act of independently controlling the spectral density of the thermal noise and/or the bandwidth of the thermal noise.

Abstract: One embodiment of the invention is directed to a method comprising an act of generating a timing signal, wherein at least some rising edges of the timing signal are based on edges of a first delay signal having a first period and a first phase, and at least some falling edges of the timing signal are based on edges of a second delay signal having a second period that is substantially the same as the first period, and a second phase that is different from the first phase. Another embodiment of the invention is directed to a programmable clock synthesizer comprising an edge-triggered circuit that receives a rising edge delay signal and a falling edge delay signal, wherein the edge-triggered circuit is adapted to generate a synthesized clock signal having rising edges triggered in response to edges of the rising edge delay signal and falling edges triggered in response to edges of the falling edge delay signal.

Abstract: One embodiment of the invention is directed to a method of extending the input range of an analog-to-digital converter (ADC) having a nominal input voltage range. The method comprises an act of mapping an over-range input voltage that falls outside of the nominal input voltage range to an over-range digital output code. Another embodiment of the invention is directed to an apparatus comprising an ADC having a nominal input voltage range, wherein the ADC is adapted to map an over-range input voltage that falls outside of the nominal input voltage range to an over-range digital output code.

Abstract: One embodiment of the invention is directed to a method, comprising acts of generating a plurality of delay signals, and processing at least first and second delay signals of the plurality of delay signals to generate a first timing signal. Another embodiment of the invention is directed to a timing signal generator to generate a plurality of timing signals. The circuit comprises a delay signal generator to generate a plurality of delay signals, and a clock synthesizer to generate the timing signals based on selected ones of the delay signals.

Abstract: One embodiment of the invention is directed to a method comprising an act of generating a timing signal, wherein at least some rising edges of the timing signal are based on edges of a first delay signal having a first period and a first phase, and at least some falling edges of the timing signal are based on edges of a second delay signal having a second period that is substantially the same as the first period, and a second phase that is different from the first phase. Another embodiment of the invention is directed to a programmable clock synthesizer comprising an edge-triggered circuit that receives a rising edge delay signal and a falling edge delay signal, wherein the edge-triggered circuit is adapted to generate a synthesized clock signal having rising edges triggered in response to edges of the rising edge delay signal and falling edges triggered in response to edges of the falling edge delay signal.

Abstract: One embodiment of the invention is directed to a method of extending the input range of an analog-to-digital converter (ADC) having a nominal input voltage range. The method comprises an act of mapping an over-range input voltage that falls outside of the nominal input voltage range to an over-range digital output code. Another embodiment of the invention is directed to an apparatus comprising an ADC having a nominal input voltage range, wherein the ADC is adapted to map an over-range input voltage that falls outside of the nominal input voltage range to an over-range digital output code.

Abstract: One embodiment of the invention is directed to a method comprising an act of performing digital correction of an offset in a system comprising an analog-to-digital converter (ADC) having a usable input range that is greater than a nominal input range, wherein the offset exists at an input of the ADC. Another embodiment of the invention is directed to a system comprising an ADC having a usable input range that is greater than a nominal input range, wherein an offset exists at an input of the ADC and the offset is corrected using digital correction.

Abstract: An offset correction circuit loop with summing nodes, a variable gain transconductance amplifier and capacitor. The input to the loop is sent to a first summing node and then to a separate circuit. The output of the separate circuit is sent to the output of the loop and to the input of a second summing node. The second summing node subtracts the circuit output from a reference voltage and sends the result to the transconductance amplifier which outputs a corrective current which is then integrated onto the capacitor to produce a corrective input offset voltage estimate.

Abstract: A method and apparatus for reducing offset errors in a variable gain circuit is offered. A first programmable gain amplifier is located in a feedforward signal path and a second programmable amplifier is connected in feedback with the first programmable gain amplifier. Each programmable gain amplifier has a separate gain control circuit so that the gain of each programmable gain amplifier can be independently controlled.

Abstract: A switched capacitor correlated double sampling circuit includes an op amp, an input sampling capacitor, and a feedback capacitor. The input capacitor samples the input signal during a first time phase and the feedback capacitor receives the signal charge from the input capacitor. No sampling switch is located between the input capacitor and the input terminal.

Abstract: A two-stage switched-capacitor CMOS Miller-compensated amplifier uses only n-channel transistors in its signal path to reduce the deleterious effects of parasitic capacitances in the signal path while still obtaining a high transconductance in both stages. A transistor inserted in series with the Miller capacitor between the output and input of the second stage of the amplifier introduces a feedforward zero in the left half of the S-plane of the circuit. By appropriately sizing the aspect ratio and properly biasing this transistor, the second pole of the amplifier is canceled with the introduced zero. Dummy transistors having their sources and drains connected (to serve as capacitors) are cross-connected between opposite polarity inputs and outputs of a differential pair of input transistors in the first stage to effectively cancel the gate-to-drain Miller-multiplied capacitance of the input transistors.

Abstract: A video clamping apparatus is described which uses transistors manufactured in a CMOS process to clamp an input video signal to a reference level during a SYNC period. A closed-loop system is provided which includes a buffer amplifier, a sample-and-hold device, a summer, a low-pass filter and a clamping circuit. The summer compares the output of the sample-and-hold device to a reference voltage which causes an output of an analog-to-digital converter to be the digital word zero.In order to maintain a high enough bandwidth of the closed loop system, a first current source is operatively coupled to the transistors of the clamping circuit during the SYNC period. When the SYNC period has ended, the first current source is decoupled from the transistors of the clamping circuit. The transconductance of the loop is, therefore, high when needed during the SYNC period.

Abstract: In a multi-stage, multi-residue interpolating analog-to-digital converter (ADC), which is suitable for pipelined implementation, inputs of at least three amplifiers are "leapfrog" switched to adjacent nodes of a first interpolation ladder having discrete voltage levels established thereon. Pairs of the amplifiers drive second interpolation ladders to establish additional discrete voltage levels (in a nominal and an overlap conversion region) at nodes of the second interpolation ladders. A bank of comparators compares a predetermined threshold voltage, e.g., ground, to several of the discrete voltage levels at the nodes of the first interpolation ladder. The switches controlling which inputs of the amplifiers are connected to which nodes of the first interpolation ladder are controlled by a logic circuit which is driven by outputs of the bank of comparators. Alternatively, the bank of comparators compares an input voltage of the ADC to voltage levels established by the first interpolation ladder.

Abstract: A two-stage switched-capacitor CMOS Miller-compensated amplifier uses only n-channel transistors in its signal path to reduce the deleterious effects of parasitic capacitances in the signal path while still obtaining a high transconductance in both stages. A transistor inserted in series with the Miller capacitor between the output and input of the second stage of the amplifier introduces a feedforward zero in the left half of the S-plane of the circuit. By appropriately sizing the aspect ratio and properly biasing this transistor, the second pole of the amplifier is canceled with the introduced zero. Dummy transistors having their sources and drains connected (to serve as capacitors) are cross-connected between opposite polarity inputs and outputs of a differential pair of input transistors in the first stage to effectively cancel the gate-to-drain Miller-multiplied capacitance of the input transistors.

Abstract: A CMOS layout enables the matching of an intentionally created parasitic capacitance to an existing parasitic capacitance, for example, a gate-to-drain capacitance of a MOSFET, with a high degree of precision. This precise matching allows a differential pair of MOSFETs acting as the input of an amplfier to have intentionally created capacitances (that match the parasitic gate-to-drain capacitances) cross-coupled between the inputs and the outputs of the differential pair. This cross-coupling of matching capacitances effectively cancels the bandwidth reducing effect of the gate-to-drain capacitances of the differential pair. The layout provides for the interdigitation of the gates of the differential pair, with each input transistor comprising at least two transistors connected together to form a single input transistor.